Bill English is stepping down as National Party Leader

Former Prime Minister Bill English is stepping down as National party leader and will be leaving Parliament later this month, he announced on Tuesday morning.

Mr English will serve his last day as leader and an MP on February 27, and will give a valedictory speech in March.

He has not nominated a replacement, instead saying it was up to the caucus MPs to decide on a new leader.

National MP Nikki Kaye said Mr English is a "rare breed of politician" and she's "really gutted" about the news.

In a tribute on her Facebook page Ms Kaye said: "He has achieved such a huge amount in 28 years. The sheer number of achievements, his depth emotionally, politically and intellectually, his understanding of policy and the machinery of government, his integrity and his strong social conscience to help some of our most vulnerable make him someone that history will look kindly on and will single out."

She says he will leave a "massive hole" in New Zealand politics and in the National party. She mentioned that Mr English is one of the people who sparked her interest in politics, and said he and former prime minister John Key helped her come back (after she took leave during her struggle with breast cancer).

Jacinda Ardern has given Mr English her best wishes on Twitter.

"Just heard the news that Bill English has decided to stand down," she wrote.

"Bill has made a huge contribution through his time in office and to politics generally.

"I admire those who serve NZ in this place, and Bill did for a long time, and he did it well."